Leftovers, but I try not to pack them the day after I have them for dinner. Or I'll change it up - slice my steak or flake my salmon over a salad, for instance, so it's not *really* the same meal (bonus - tastes good cold!).

It's fun to shop for containers to carry lunch in. My DH wants to eat primal now so I pack really healthy lunches for him instead of sandwiches, chips and candy bars plus soda. I found a nice container with double dishes, that way he can take out one and zap in the microwave and have salad greens or fruit in the other. He drinks filtered water and green tea with lime and stevia and he likes it as much as Pepsi now. He keeps a bag of macadamia nuts and goji berries in his desk and I usually send a banana or gala apple.